It is known to supply photographic processors, in which sensitized photographic material is passed through tanks containing processing solution, with replenishment solution from time-to-time in accordance with the quantity of material as measured passing therethrough in order to maintain the activity of the processing solution. Usually, the type of material being processed is also noted and the amount of replenishment adjusted accordingly. Furthermore, processors are inspected by operators from time-to-time, usually before they are brought into operation after a shutdown, to ensure that the solutions in the tanks are up to the required levels.
Tanks, of whatever configuration, of photographic processors are typically replenished with an excess quantity of solution in order to ensure that the required minimum levels are maintained at all times. This excess arises for several reasons, for example: (a) to avoid the need for frequent inspection of the tank levels by the operator; (b) to offset the carryover of solution by the material from one tank to the next, which may be excessive, or may gradually increase with time, due to wear of squeegees located at tank exits; and (c) the need to offset any loss due to minor leakage that might not immediately be noticed. At least some of the excess solution may immediately go to waste through an overflow pipe. This loss is clearly an unwanted initial cost, but it is also a cost in terms of the need to dispose of and/or reclaim undesirable or expensive materials, and thus can be an environmental problem.
It is one object of the present invention to provide control of photographic processing such that consumption of processing solutions and production of waste solutions are reduced. It is another object of the invention to provide processing control such that the chemical activity of the processor is maintained in a more consistent state.